In his math class, Michael took 5 tests. His scores were 91, 86, 84, 98, and 76. What was his average score on the tests?
The average is the sum of his scores divided by the number of scores. There are 5 scores and their sum is $91 + 86 + 84 + 98 + 76 = 435$ His average score is $435 \div 5 = 87$.